1. Field of the Disclosure
Embodiments described herein relate to the field of wireless communication devices and systems. More particularly, embodiments described herein relate to the field of signal processing and electromagnetic interference (EMI) rejection for wireless communications devices and systems.
2. Description of Related Art
In the context of the present disclosure, a wireless device is understood as a device having a wireless communication capability. The device may be mobile or fixed to a station. In the field of wireless communications, wireless devices are used to receive and transmit a signal to and from another wireless device. Signals in the electro-magnetic radio-frequency (RF) spectral domain are used for wireless communications, ranging in frequency from a few MHz (Mega-Hertz) up to hundreds of GHz (Giga-Hertz). Use of the license free Industrial, scientific and medical (ISM) spectral band, shared among various types of wireless devices, is attractive for many low power wireless applications. Thus, electromagnetic interference (EMI) between different wireless devices becomes an issue for signal processing. Furthermore, many consumer electronic products such as liquid crystal displays (LCDs), flat screen panels, WiFi routers, Bluetooth devices, microwave ovens, and others use circuitry operating at these frequencies, therefore emitting radiation causing electro-magnetic interference (EMI) to a wireless device used for communication.
State-of-the-art approaches for removing EMI include sophisticated transceivers to ensure device functionality in the presence of other devices in the vicinity. Unrelated devices in the vicinity of a transceiver may be operating on a nearby channel, or even on the same channel as the transceiver, in an asynchronous, time shared mode. Sophisticated transceivers impose a significant energy load on battery powered devices. Some techniques for EMI rejection use transceivers having heterodyne receivers and sophisticated modulation/demodulation techniques such as digital signal processing (DSP). Some embodiments use spread-spectrum techniques such as frequency hopping and/or DSSS, typically expensive to implement and which use high battery power. Intensive use of battery power is especially burdensome for mobile wireless devices, seriously impairing operating life from a specified battery capacity.
What is needed is a device and a method for using a device providing good rejection of EMI without imposing significant power consumption.